Reduction of Turbulence Interaction Noise Through Airfoils With Perforated Leading Edges

Geyer, Thomas; Lucius, Andreas; Schrödter, Marcus; Schneider, Marc; Sarradj, Ennes

doi:10.3813/aaa.919292

Cited by 44 publications

(31 citation statements)

References 37 publications

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“…2011; Geyer, Sarradj & Giesler 2012; Roger, Schram & De Santana 2013; Sarradj & Geyer 2014; Roger & Moreau 2016; Avallone, Casalino & Ragni 2018; Geyer et al. 2019; Sinnige et al. 2019; Zamponi et al.…”

Section: Introductionunclassified

Rapid distortion theory of turbulent flow around a porous cylinder

2021

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Section: Introductionunclassified

Rapid distortion theory of turbulent flow around a porous cylinder

2021

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“…More recently, the use of airfoils with slitted leading edges has been investigated [16]. Another possible method is the modification of the material of the leading edge, for example by using flow-permeable materials [4,17,18]. Besides the experimental work, there are also some analytical and numerical investigations.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Airfoil Leading Edge Combs for Turbulence Interaction Noise Reduction

2020

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The interaction of a turbulent flow with the leading edge of a blade is a main noise source mechanism for fans and wind turbines. Motivated by the silent flight of owls, the present paper describes an experimental study performed to explore the noise-reducing effect of comb-like extensions, which are fixed to the leading edge of a low-speed airfoil. The measurements took place in an aeroacoustic wind tunnel using the microphone array technique, while the aerodynamic performance of the modified airfoils was captured simultaneously. It was found that the comb structures lead to a noise reduction at low frequencies, while the noise at high frequencies slightly increases. The most likely reasons for this frequency shift are that the teeth of the combs break up large incoming turbulent eddies into smaller ones or that they shift turbulent eddies away from the airfoil surface, thereby reducing pressure fluctuations acting on the airfoil. The aerodynamic performance does not change significantly.

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“…Future work could investigate more sophisticated porosity models, such as those developed in [9] and further interrogate the model with a broader experimental study. The value of such work would be to isolate the acoustic scattering and absorption effects from alternative mechanisms that may be present; for instance modifications to the incident disturbance, as a thicker boundary layer displacing the turbulence further from the surface effectively increasing leading edge thickness to reduced gust interaction noise as described in [5].…”

Section: Discussionmentioning

confidence: 99%

“…Geyer has investigated porous trailing edges [3], finding improved aerodynamic performance, whilst still attaining noise reductions. Equivalent investigations into porous leading-edges are much less extensive; we note the work of Roger et al [4] and recent investigations into leading edge perforations on a thick aerofoil [5]. Therefore this paper includes a preliminary experimental investigation of the aeroacoustic performance of porous leading edges on a flat plate for which experimental data is not widely available.…”

Section: Introductionmentioning

confidence: 99%

A Semi-analytic and Experimental Study of Porous Leading Edges

Priddin

Paruchuri

Joseph

et al. 2019

25th AIAA/CEAS Aeroacoustics Conference

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This paper presents a semi-analytical investigation into the aeroacoustic properties of aerofoils with porous leading edges, complemented by an experimental study of flat rigid plates with a perforated leading section. Interest in partially porous aerofoils arises from their potential to reduce noise emission from wind turbines and commercial aeroplanes whilst maintaining aerodynamic performance. Developing theoretical models will be helpful for understanding the dominant physical mechanisms and thereby designing optimal implementations. We consider a simple theoretical model that captures acoustic scattering from a finite plate with a porous leading edge. This yields a matrix Wiener-Hopf problem which is solved by an iterative approach that facilitates reliable and rapidly computable solutions. This allows a quantification of acoustic reductions that may be anticipated, and a comparison between studying a porous leading edge on a finite and semi-infinite plate. Experimental results are presented for a flat rigid plate with a perforated leading edge section that demonstrate some qualitative agreement with the theoretical model.

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Reduction of Turbulence Interaction Noise Through Airfoils With Perforated Leading Edges

Cited by 44 publications

References 37 publications

Rapid distortion theory of turbulent flow around a porous cylinder

Rapid distortion theory of turbulent flow around a porous cylinder

Experimental Study of Airfoil Leading Edge Combs for Turbulence Interaction Noise Reduction

A Semi-analytic and Experimental Study of Porous Leading Edges

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